The present invention relates to an automotive air-conditioning apparatus for air-conditioning the interior cabin of an automobile, and more particularly to an automotive air-conditioning apparatus for increasing the amount of air fed from an air blower in a demisting mode so as to be greater than the amount of air fed from the air blower in an automatic adjusting mode and for controlling the opening of an air mixing damper dependent on an ambient-air temperature.
Automotive air-conditioning apparatus have heretofore been employed to air-condition the automobile passenger compartment or cabin and also prevent the front windshield from getting frosted for thereby giving the driver clear visibility through the front windshield to allow the driver to drive the automobile with safety. One such automotive air-conditioning apparatus is disclosed in Japanese Laid-Open Utility Model Publication No. 56-108911 published on Aug. 24, 1981. The disclosed automotive air-conditioning apparatus operates in a demisting mode by controlling an air mixing damper in a maximum heating mode and controlling an air blower to supply a maximum amount of air. More specifically, the air-conditioning apparatus includes a first control circuit for automatically controlling the air mixing damper to adjust the ratio of a mixture of cool air and hot air, and a second control circuit for selectively controlling the air mixing damper in a full cooling mode or a full heating mode. When the full cooling mode or the full heating mode is selected, the air mixing damper control system is separated from the first control circuit, and is controlled only by the second control circuit. The second control circuit is also capable of rotating the air blower at a high speed. When the second control circuit is selected, it enables the air blower to rotate at a high speed.
With the disclosed arrangement, however, when the full cooling mode or the full heating mode is selected, the automobile cabin is brought into a maximum cooling mode or a maximum heating mode irrespectively of ambient air conditions. This prevents the automobile cabin from being air-conditioned for the best comfort of the driver and passengers, if any, especially during seasons of comfortable weather.
Japanese Utility Model Publication No. 53-49143 published on Nov. 25, 1978 reveals an automobile demister or defroster for discharging maximum heating air from a demisting-air outlet by generating a signal for a maximum heating capability when the front windshield is to be demisted. The disclosed automobile demister includes a switch connected to thermosensitive resistors, for example, and interlinked with a manual selector. When the manual selector is in a demisting position, it produces the aforesaid signal to open the demisting-air outlet to introduce hot air into the automobile cabin.
The automobile demister of the above construction is however disadvantageous in that since the demisting control is performed independently of ambient air conditions, the automobile cabin cannot be air-conditioned as desired, and the driver and passengers, if any, will feel excessively hot.